Re: Chained fetch ratio

From: <bialik_at_wis.weizmann.ac.il>
Date: Tue, 05 May 1998 15:12:34 -0600
Message-ID: <6inrri$cqf$1@nnrp1.dejanews.com>

Hi.

Probably, you didn't analyze your tables. The chained-rows stats are collected by : ANALYZE TABLE <Table_Name> LIST CHAINED ROWS; It assumes that you already have table named CHAINED_ROWS defined in your db( UTLCHAIN.SQL file is supposed to contain these definitions ).

Anyway, run following statement :
SELECT NAME,VALUE FROM V$SYSSTAT WHERE NAME LIKE 'table%' ORDER BY NAME;
Look for the VALUE for 'table fetch continued rows'. If it's > 0 - you are actually accessing chained rows and the performance suffers.

Good luck. Michael.
In article <354F2F3A.87C00EF9_at_microware.demon.co.uk>#1/1, ij_at_microware.demon.co.uk wrote:
>
> Hi all,
>
> Nice easy one for a guru somewhere. According to the analysis software
> that I'm using I have a 'PCTFREE too low for a table' error reported
> against 'chained fetch ratio'. Ok, I understand the concept of chained
> rows, but how do I find out which table the error refers to. I've
> checked every table in the database that I can find with a column
> 'chain_cnt' and they all report zero. Don't know where else to look.
>
> Many thanks for any assistance.
>
> TIA
>
> --
> ************************************************************
> Ian Jennings
> Microware Data Services
>
> This post is made entirely from recycled ones and noughts
> ************************************************************
>
>

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